A. Field of the Invention
The present invention relates generally to slide projectors and more particularly to control apparatus for tray drive and slide change functions of a slide projector wherein servo operation of the tray drive position is achieved by dual photodetectors and position apertures provided on a circumferential, coded aperture ring corresponding to the respective slide tray positions.
B. Description of the Prior Art
Various control apparatus are known for slide projectors to control positioning of the slide tray to a slide position and the operation of a slide changer to present the slide to a viewing position. These various control apparatus are controllable in either a manual mode or a random access mode. Arrangements of this type, for example, are disclosed in U.S. Pat. Nos. 3,296,727, 3,225,652, 3,299,554, 3,895,864, 3,907,414, 3,924,942, 3,566,370, 4,041,457, 3,510,215, 3,644,027, 3,733,122, 3,652,155, 3,623,803, 3,700,320 and 3,732,546.
While the above described control apparatus of the prior art are generally suitable for their intended use, it would be desirable to more accurately control slide tray positioning and provide the integrated control of slide tray movement and slide changer movement.